Galactokinase deficiency

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Galactokinase deficiency
Other namesGalactosemia type 2 or GALK deficiency,[1]
Galactitol
SpecialtyEndocrinology Edit this on Wikidata

Galactokinase deficiency is an

cataracts during the first weeks or months of life, as a result of the accumulation, in the lens, of galactitol, a product of an alternative route of galactose utilization. The development of early cataracts in homozygous affected infants is fully preventable through early diagnosis and treatment with a galactose-restricted diet. Some studies have suggested that, depending on milk consumption later in life, heterozygous carriers of galactokinase deficiency may be prone to presenile cataracts at 20–50 years of age.[3]

Signs and symptoms

Causes the elevation of galactose in blood (galactosemia) and urine (galactosuria).[citation needed]

When the patient consumes galactose via their diet, it will result in galactitol accumulation. Which can result in cataracts.[4]

Genetics

Galactokinase deficiency has an autosomal recessive pattern of inheritance.

Galactokinase deficiency is an autosomal recessive disorder,

carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.[citation needed
]

Unlike

lens of the eye.[6] Cataracts can present as a failure to develop a social smile and a failure to visually track moving objects.[citation needed
]

Gene structure

The human GALK1 gene contains 8 exons and spans approximately 7.3 kb of genomic DNA. The GALK1 promoter was found to have many features in common with other housekeeping genes, including high GC content, several copies of the binding site for the

RACE PCR indicated that the GALK1 mRNA is heterogeneous at the 5-prime end, with transcription sites occurring at many locations between 21 and 61 bp upstream of the ATG start site of the coding region. In vitro translation experiments of the GALK1 cDNA indicated that the protein is cytosolic and not associated with the endoplasmic reticulum membrane.[3]

Diagnosis

Diagnosis is established by high blood levels of galactose, normal activity of the enzyme

galactose-1-phosphate uridyltransferase and reduced or no activity of galactokinase in RBCs.[7]

Treatment

Medical care

  • Treatment may be provided on an outpatient basis.
  • Cataracts that do not regress or disappear with therapy may require hospitalization for surgical removal.

Surgical care

  • Cataracts may require surgical removal.

Consultations

  • Biochemical geneticist
  • Nutritionist
  • Ophthalmologist

Diet

  • Diet is the foundation of therapy. Elimination of lactose and galactose sources suffices for definitive therapy.

Activity

See also

References

  1. ^ a b Online Mendelian Inheritance in Man (OMIM): Galactokinase Deficiency - 230200
  2. S2CID 20585794
    .
  3. ^
    PMID 10521295
    .
  4. ^ Harper's Biochemistry.[full citation needed]
  5. PMID 10570908
    .
  6. ^ a b Roth, KS (September 10, 2007). "Galactokinase Deficiency". eMedicine. WebMD. Retrieved 2008-08-08.
  7. ISBN 978-0-323-29568-0
    .
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